To make sure the @2x has been used for 2X resolution screen, I have made the @2x image a little darker than the 1x image, I'm sure the @2x image can be loaded and show correctly before the 2017.11.3 release. The code I use is nothing special, it just use the TileMap.new to pass in the texture.

Please read my comments carefully you would notice that It's not possible that it always used the @1x image, To test the @2x image is really used, the color of @2x image is different from the @1x one.And it's not possible the size of textures, if the size is too large, it would just show nothing.

I've looked through the code in my new game, and the difference between Atilim's example and my code is that I use a TexturePack and getTextureRegion() instead of using Texture directly. Maybe it's because of that?